In a vehicle, a transmission is interposed between an internal combustion engine and drive wheels. In the transmission, driving force and running speed of the driving wheel are changed in accordance with the running conditions of the vehicle which change in a wide range, thereby allowing the performance of the internal combustion engine to be sufficiently effected. Among the transmissions, there is known an automatic non-stage transmission for vehicles having: a driving side adjustable pulley comprising a fixed pulley member which is fixed to a driving side shaft and a movable pulley member which is attached to the driving side shaft so as to be movable both toward and away from the fixed pulley member; a driven side adjustable pulley comprising a fixed pulley member which is fixed to a driven side shaft and a movable pulley member which is attached to the driven side shaft so as to be movable both toward and away from the associated fixed pulley member; and a belt reeved (wound) around the pulleys, wherein the width of respective grooves defined between the respective pairs of pulley members is decreased and increased and the rotating contact radius of the belt reeved around the pulleys is decreased and increased, thereby performing a variable speed control to achieve a change gear ratio.
Such an automatic non-stage transmission is disclosed in, for instance, JP-U-61-24753. According to the transmission disclosed therein, a drive shaft is formed as a hollow shaft, and the portion which rotates integrally with a torque converter or an engine of a fluid joint and an oil pump gear are coupled by an oil pump drive shaft which penetrates in the hollow portion of the drive shaft. An oil chamber in the central portion of the oil pump which is connected to a lock-up operation control circuit of a hydraulic pressure control unit and a lock-up clutch oil chamber in the torque converter or fluid joint are connected by an annular oil passage which is formed between the drive shaft hollow portion and the oil pump drive shaft. One end of the drive shaft faces the lock-up clutch oil chamber and the other end of the drive shaft faces the oil chamber of the oil pump. Therefore, the forces by the hydraulic pressures in both of the oil chambers which act on the drive shaft are always balanced so as not to generate a force in the shaft direction. Thus, there is no need to use a bearing of a large capacity in consideration of the force in the shaft direction. The non-stage transmission can be miniaturized and its weight is reduced.
In the automatic non-stage transmission using a metal belt which is reeved around the pulleys, since the motive power is transferred by the metal friction between the metal belt and the pulley members, a large force is applied to the metal belt. Therefore, a method and apparatus to supply an amount of lubricating oil is important. However, there is a case where the lubrication becomes improper or insufficient due to the path of the lubricating oil, the capacity of the oil pump, and the like.
That is, in the lubrication of the metal belt, it is important to positively supply the lubricating oil to the necessary portion of the belt. Since the metal belt is moved (rotated) while being reeved around the pulleys, the lubricating oil collides with the metal belt and is scattered and the supplying method of the lubricating oil is very difficult. Therefore, there is a case where the lubricating oil is supplied to the necessary portion of the belt by the oil pump through a thin nozzle at a predetermined pressure (ordinarily, a low pressure of 1 to 3 kg/cm.sup.2). In this case, the lubricating oil is almost rectilinearly emitted from the nozzle for a predetermined distance and is applied to the necessary portion of the belt.
However, to emit the lubricating oil to the necessary belt portion, an oil pump of a large capacity is necessary, causing the size of the oil pump to become large. Also, there are inconveniences such that, due to the scattering described above, more lubricating oil than is needed is emitted from the nozzle and the work loss of the transmission increases.
On the other hand, after the pressurized lubricating oil collides with the rotating metal belt and is scattered by the centrifugal force, the lubricating oil is returned to the oil pan along the transmission casing and other internal parts, so that the lubricating oil is not effectively used.
In detail, as shown in FIG. 4, in an automatic non-stage transmission 102, a metal belt 104 rotates in moving direction (shown by arrows) and in the case of the maximum change gear ratio (full low), the rotating contact radius of the metal belt 104 decreases on the driving side pulley 106 and increases on the driven side pulley 108 (shown by a metal belt 104-A in FIG. 4). On the contrary, in the case of the minimum change gear ratio (overdrive), the rotating radius of the metal belt 104 increases on the pulley 106 and decreases on the pulley 108 (shown by a metal belt 104-B in FIG. 4). Even during backward movement of the vehicle, the metal belt 104 rotates in the same direction.
A lubricating oil pipe 114 constitutes a lubricating oil supplying means 112 and is arranged in a space 110 which is surrounded by pulley 106, pulley 108, and metal belt 104. The lubricating oil to the metal belt 104 is emitted from a discharge nozzle (not shown) formed in the lubricating oil pipe 114. The lubricating oil which collides with the rotating metal belt 104 is transferred along an inner surface 116a of a transmission casing 116 and other parts and is returned to an oil pan (not shown). As compared with the portion of the metal belt 104 on the side of pulley 108, the portion of the metal belt 104 on the side of pulley 106 is far away from the oil pipe 114 and thus the discharge nozzle. In addition, since the position of the metal belt 104 on the pulleys changes as mentioned above, the lubricating state becomes disadvantageous. Moreover, when the change gear ratio changes, since the metal belt moves in the shaft directions of the shafts 118 and 120, there is an inconvenience such that the lubricating state beCOmes unstable.
It is therefore an object of the invention to provide an automatic non-stage transmission for vehicles in which, in order to eliminate the foregoing inconveniences, lubricating oil which is scattered by the rotating metal belt and flows along the inner surface of the transmission casing is induced or directed to the side of the metal belt, so that even if a change gear ratio changes, the lubrication of the metal belt can be efficiently accomplished and the lubricating oil can be effectively used.